1. Field of the Present Invention
The invention is directed to a mixing kneader device for the production of raw dough, comprising a closed housing, a product feed opening, a discharge outlet and continuously working work elements in the housing.
2. Background Prior Art
A multitude of processing machines are currently being used for dough making. Pasta makes up an increasing proportion of the foodstuffs prepared via the dough die. The shaping is effected for the most part by means of an extrusion process in which the viscous dough is pressed through the press dies at high pressures of, e.g., 80 to 120 bar and cut to a desired length.
Different binding forces are utilized for the shaping and for the subsequent retention of shape. The so-called protein structure is the classic binding. The protein structure is the net-like, spatial interlinking of all protein cells which hold together the starch which is in crystalline form. The protein structure can be changed and re-structured as often as desired, but only as long as there is sufficient water and the protein does not coagulate due to higher temperatures. Vegetable albumin behaves in a way very similar to the hen's egg. When a hen's egg is broken in cold water, it virtually retains its shape if this is done carefully. When stirred briskly or beaten, a watery egg soup is obtained which is colored by the egg. Its behavior is completely different when the same egg is broken in boiling water. With a few seconds, the egg takes on an almost bizarre outline shape and retains this without mechanical intervention. In order to obtain a fine distribution of the egg material, the entire contents of the egg must be beaten and stirred vigorously immediately after being thrown into the boiling water. The finely distributed egg particles thus retain their refined shape. In the presence of heat, the coagulation of the egg mass takes place in the egg immediately, within seconds, and is irreversible. All albumin-containing raw materials processed with heat in the foodstuffs industry must take these facts into account. This is true particularly in the case of extruded products.
The temperature boundary value before the irreversible point is between 60.degree. and 80.degree. C.; that is, already below the actual boiling temperature (that is, below 100.degree. C.). If a product mass is brought into the range of 100.degree. C. or more during the mixing, kneading and dough forming, only an insufficient protein structure is developed in a subsequent shaping process, e.g. for classic pasta such as macaroni.
Over the past three to four decades, two independent foodstuffs processing methods have come into use: